467A - George and Accommodation.cpp

#include "iostream"

using namespace std;

int main()
{
    int n;
    int result = 0;

    cin >> n;

    for (int i = 0; i < n; ++i)
    {
        int p, q;
        cin >> p >> q;

        if (q >= p + 2)
            result++;
    }

    cout << result;

    return 0;
}