View Compilation Error

0_0_16785993_29816.cpp: In function 'int main()':
0_0_16785993_29816.cpp:13:5: error: 'int64' was not declared in this scope
     int64 sum,n;
     ^
0_0_16785993_29816.cpp:14:26: error: 'n' was not declared in this scope
     while (scanf("%lld",&n)!=EOF) {
                          ^
0_0_16785993_29816.cpp:15:9: error: 'sum' was not declared in this scope
         sum=((n*(n+1)/2%10000)*(n*(n+1)/2%10000))%10000;
         ^