View Compilation Error

0_0_15724396_28188.cpp: In function 'int main()':
0_0_15724396_28188.cpp:5:2: error: '_int64' was not declared in this scope
  _int64 f[55]={1,1,1,2};
  ^
0_0_15724396_28188.cpp:6:19: error: 'f' was not declared in this scope
  for(i=4;i<55;i++)f[i]=f[i-1]+f[i-2];
                   ^
0_0_15724396_28188.cpp:11:25: error: 'f' was not declared in this scope
         printf("%lld\n",f[b-a+1]);
                         ^