View Compilation Error

0_0_15734836_1576.cpp: In function 'int main()':
0_0_15734836_1576.cpp:4:5: error: '_int64' was not declared in this scope
     _int64 n,i;
     ^
0_0_15734836_1576.cpp:5:9: error: expected ';' before 'a'
  _int64 a[55]={1,2};
         ^
0_0_15734836_1576.cpp:6:6: error: 'i' was not declared in this scope
  for(i=2;i<55;i++)a[i]=a[i-1]+a[i-2];
      ^
0_0_15734836_1576.cpp:6:19: error: 'a' was not declared in this scope
  for(i=2;i<55;i++)a[i]=a[i-1]+a[i-2];
                   ^
0_0_15734836_1576.cpp:7:21: error: 'n' was not declared in this scope
  while(~scanf("%d",&n))
                     ^
0_0_15734836_1576.cpp:9:20: error: 'a' was not declared in this scope
   printf("%I64d\n",a[n-1]);
                    ^