#include <bits/stdc++.h>

#define FOR(i, n) for(lli i = 0; i < (lli)(n); ++i)
#define FORU(i, a, b) for(lli i = (lli)(a); i < (lli)(b); ++i)
#define FORD(i, a, b) for(lli i = (lli)(b)-1; i >= (lli)(a); --i)
#define ALL(x) (x).begin(), (x).end()

#define X(A) get<0>(A)
#define Y(A) get<1>(A)
#define Z(A) get<2>(A)
#define W(A) get<3>(A)

#define mt make_tuple
#define pb push_back



using namespace std;
using lli = long long int;

using pii   = tuple<lli, lli>;
using piii  = tuple<lli, lli, lli>;
using vi    = vector<lli>;
using vii   = vector<pii>;
using viii  = vector<piii>;
using vvi   = vector<vi>;
using vvii  = vector<vii>;
using vviii = vector<viii>;
using vb    = vector<bool>;
using vvb   = vector<vb>;
// =====

const int DIM = 50 * 50 + 1;
int nbRows, nbCols, nbDim;

typedef bitset<DIM> Matr;

struct PermVect {
    vector<Matr> v;
    vector<int> lineId;

    PermVect(){}
    PermVect(size_t n) {
        v.resize(n);
        lineId.resize(n);
        FOR(i, lineId.size()) lineId[i] = i;
    }

    Matr& operator[](size_t pos) { return v[lineId[pos]]; }
    const Matr& operator[](size_t pos) const { return v[lineId[pos]]; }
    void swapRow(size_t i, size_t j) {
        swap(lineId[i], lineId[j]);
    }
};

PermVect crosses;

inline size_t at(int row, int col) {
    return row * nbCols + col;
}

void dump() {
    FOR(rowId, nbDim) {
        const Matr& row = crosses[rowId];
        FOR(pos, nbDim)
            printf("%c", row[pos]?'1':'0');
        printf("  %c\n", row[nbDim]?'1':'0');
    }
    puts("===");
}

bool solve() {
    for(int trigAt=0; trigAt < nbDim; ++trigAt) {
        bool found = false;
        for(int dim=trigAt; dim < nbDim; ++dim) {
            if(!crosses[dim][trigAt])
                continue;
            found = true;
            crosses.swapRow(trigAt, dim);
            for(int nDim=trigAt+1; nDim < nbDim; ++nDim) {
                if(crosses[nDim][trigAt])
                    crosses[nDim] ^= crosses[trigAt];
            }
            break;
        }
        if(!found)
            return false;
    }
    for(int dim=nbDim-1; dim >= 0; --dim) {
        for(int nDim=dim-1; nDim >= 0; --nDim) {
            if(crosses[nDim][dim])
                crosses[nDim] ^= crosses[dim];
        }
    }
    return true;
}

int main(void) {
    scanf("%d%d", &nbRows, &nbCols);
    nbDim = nbRows * nbCols - 1;
    crosses = PermVect(nbDim);
    FOR(row, nbRows) {
        FOR(col, nbCols) {
            FOR(i, nbCols)
                crosses[at(row, col)].set(at(row, i));
            FOR(i, nbRows)
                crosses[at(row, col)].set(at(i, col));
        }
    }

    FOR(row, nbRows) {
        getchar();
        FOR(col, nbCols)
            crosses[at(row, col)][nbDim] = getchar() == 'B';
    }


    if(!solve()) {
        dump();
        puts("No");
    }
    else {
        puts("Yes");
        set<int> ids;
        FOR(row, nbDim)
            if(crosses[row][nbDim])
                ids.insert(row);
        printf("%lu\n", ids.size());
        FOR(i, nbDim) {
            if(ids.find(crosses.lineId[i]) != ids.end())
                printf("%lld %lld\n", (i/nbCols) + 1, (i%nbCols) + 1);
        }
    }
    return 0;
}