#include <iostream>
using namespace std;
int main() {
int m;
cout << "Enter your mark from 0 to 100: ";
cin >> m;
if (m >= 90)
{
cout << "A";
}
else if(m >= 80)
{
cout << "B";
}
else if (m >= 70)
{
cout << "C";
}
else if (m >= 60)
{
cout << "D";
}
else
{
cout << "F";
}
return 0;
}
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