View Compilation Error

0_0_17902868_31850.cpp: In function 'int main()':
0_0_17902868_31850.cpp:10:3: error: '_int64' was not declared in this scope
   _int64 m,n,sum;
   ^
0_0_17902868_31850.cpp:11:23: error: 'm' was not declared in this scope
   scanf("%I64d%I64d",&m,&n);
                       ^
0_0_17902868_31850.cpp:11:26: error: 'n' was not declared in this scope
   scanf("%I64d%I64d",&m,&n);
                          ^
0_0_17902868_31850.cpp:12:3: error: 'sum' was not declared in this scope
   sum=m+n;
   ^