NUMROUTE

#include <iostream>
using namespace std;
long long n, s, d, k;
long long matrix[75][75][75] = { 0 };
int main()
{
    cin >> n;
    for (long long i = 1; i <= n; ++i)
    {
        for (long long j = 1; j <= n; ++j)
        {
            cin >> matrix[i][j][1];
        }
    }cin >> s >> d >> k;
    for (long long t = 2; t <= k; ++t)  // matrix power
    {
        for (long long i = 1; i <= n; ++i)//row
        {
            for (long long j = 1; j <= n; ++j)//column
            {
                for (long long f = 1; f <= n; ++f)  // multiplication iterator
                    matrix[i][j][t] += matrix[i][f][t - 1] * matrix[f][j][1]; // the real work happens here
                //if (t == k){cout << matrix[i][j][t] << "( " << i << "," << j << " )";} testing
            }
        }
    }
    cout << matrix[s][d][k];
    return 0;
}