67p. 5u.

#include <iostream>
#include <fstream>

using namespace std;

int main()
{
    int n, s, s1, sum= 0;
    ifstream a ("duom.txt");
    a >> n;
    for (int i=1; i<=n; i++)
    {
        a >> s;
        a >> s1;
       if (s1 < s)
            sum = sum + 1;

    }
    cout << sum ;
    return 0;
}