程式碼如下：

#include <bits/stdc++.h>
#define Max 5000010
using namespace std;
int euler[Max];
int main()
{
    int l, r;

    scanf( "%d%d", &l, &r);
    euler[1] = 1;
    for( int i = 2;i <= r; i++)
        euler[i] = i;
    for( int i = 2;i <= r; i++)
        if( euler[i] == i)
            for( int j = i;j <= r; j += i)
                euler[j] = euler[j] / i * ( i - 1);
    printf( "%d\n", min_element( euler + l, euler + r + 1) - euler);
    return 0;
}