View Compilation Error

0_0_21419648_10454.cpp: In function 'int main()':
0_0_21419648_10454.cpp:55:9: error: '_int64' was not declared in this scope
         _int64 n,m;
         ^
0_0_21419648_10454.cpp:56:29: error: 'n' was not declared in this scope
         scanf("%I64d%I64d",&n,&m);
                             ^
0_0_21419648_10454.cpp:56:32: error: 'm' was not declared in this scope
         scanf("%I64d%I64d",&n,&m);
                                ^