View Compilation Error

0_0_21572537_27559.cpp:2:1: error: '_int64' does not name a type
 _int64 jiechen(int i)
 ^
0_0_21572537_27559.cpp: In function 'int main()':
0_0_21572537_27559.cpp:13:5: error: '_int64' was not declared in this scope
     _int64 score;
     ^
0_0_21572537_27559.cpp:14:13: error: expected ';' before 's'
     _int64  s[1000]={0};
             ^
0_0_21572537_27559.cpp:15:5: error: 's' was not declared in this scope
     s[1]=0;
     ^
0_0_21572537_27559.cpp:26:13: error: 'score' was not declared in this scope
             score=jiechen(m);
             ^
0_0_21572537_27559.cpp:26:28: error: 'jiechen' was not declared in this scope
             score=jiechen(m);
                            ^