I don't know the issue

#include
using namespace std;

void small(int n){

int m;
int i = 0;
long long int rev = 0;
while(n>0){
    m = n%10;
    if(m > 9-m){
       if(m == 9 && n/10 == 0){}else{
        rev = rev + (9-m)*pow(10,i);}
    }else{
        rev = rev + m*pow(10,i);
    }
    i++;
    n = n/10;
}
cout<<rev;

}

int main(){

long long int n;
cin >> n;
small(n);

}

// Its showing wrong answer