View Compilation Error

0_0_39099236_25455.cpp: In function 'int main()':
0_0_39099236_25455.cpp:40:33: error: 'b' was not declared in this scope
   40 |                         if(j >= b[i] + 1) f[i][j] = f[i][j - 1] + f[i - 1][j] - f[i - 1][j - 1 - b[i]];
      |                                 ^