#include<iostream>
#include<cmath>
using namespace std;
int main()
{
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
int n , a , b;
cin >> n >> a >> b;
while(n >= a && n >= b)
{
n = n %( a + 2 * b);
if( n >= b )
{
n = n - b;
}
if (n >= a)
{
n = n - a;
}
}
cout << n;
return 0;
}
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