View Compilation Error

0_0_36680257_6426.cpp:18:1: error: '_int64' does not name a type
 _int64 a[36][36];
 ^
0_0_36680257_6426.cpp: In function 'void solve(int)':
0_0_36680257_6426.cpp:23:2: error: 'a' was not declared in this scope
  a[0][0]=1;
  ^
0_0_36680257_6426.cpp: In function 'int main()':
0_0_36680257_6426.cpp:44:34: error: 'a' was not declared in this scope
   printf("%d %d %I64d\n",sum,n,2*a[n][n]);
                                  ^