xltuoi c++

#include<bits/stdc++.h>
using namespace std;
int a;
int main()
{    
    //freopen("XLTUOI.inp","r",stdin);
    //freopen("XLTUOI.out","w",stdout);
    cin>>a;
    if ((0<=a)&&(a<=1)) cout<<"So sinh";
    if ((2<=a)&&(a<=9)) cout<<"Nhi dong";
    if ((10<=a)&&(a<=15)) cout<<"Thieu nien";
    if ((16<=a)&&(a<=32)) cout<<"Thanh nien";
    if ((33<=a)&&(a<=50)) cout<<"Trung nien";
    if (a>50) cout<<"Nguoi lon tuoi";
}