View Compilation Error

0_0_36622023_6851.cpp: In function 'long long int S(long long int, long long int)':
0_0_36622023_6851.cpp:22:8: error: 'c' was not declared in this scope
     if(c[n][m]) return c[n][m];
        ^
0_0_36622023_6851.cpp:25:9: error: 'c' was not declared in this scope
         c[n][m] = 1;
         ^
0_0_36622023_6851.cpp:27:9: error: 'c' was not declared in this scope
         c[n][m] = S(n-1,m-1)%mod + ((S(n-1,m)%mod)*m)%mod;
         ^
0_0_36622023_6851.cpp:29:12: error: 'c' was not declared in this scope
     return c[n][m]%mod;
            ^