View Compilation Error

0_0_28832529_20731.cpp:4:1: error: '__int64_t' does not name a type
 __int64_t a,b;
 ^
0_0_28832529_20731.cpp: In function 'int main()':
0_0_28832529_20731.cpp:8:16: error: 'a' was not declared in this scope
     while(cin>>a>>b && a!=0 && b != 0)
                ^
0_0_28832529_20731.cpp:8:19: error: 'b' was not declared in this scope
     while(cin>>a>>b && a!=0 && b != 0)
                   ^