View Compilation Error

0_0_21738003_9183.cpp: In function 'int main()':
0_0_21738003_9183.cpp:7:9: error: '_int64' was not declared in this scope
         _int64 ans = a + b;
         ^
0_0_21738003_9183.cpp:8:12: error: 'ans' was not declared in this scope
         if(ans < 0) putchar('-'), ans = -1 * ans, printf("%I64X\n", ans);
            ^