View Compilation Error

0_0_38421211_17504.cpp: In function 'int main()':
0_0_38421211_17504.cpp:8:5: error: 'int64' was not declared in this scope
     int64 ac[21],bc[21],ans[21];
     ^
0_0_38421211_17504.cpp:9:5: error: 'ac' was not declared in this scope
     ac[1]=2;
     ^
0_0_38421211_17504.cpp:10:5: error: 'bc' was not declared in this scope
     bc[1]=1;
     ^
0_0_38421211_17504.cpp:15:9: error: 'ans' was not declared in this scope
         ans[i]=2*bc[i-1]+2;
         ^
0_0_38421211_17504.cpp:17:5: error: 'ans' was not declared in this scope
     ans[1]=2;
     ^