#!/usr/bin/env python3
# -*- coding: utf-8 -*-
tim, dis = 0, 0

input_file = open("input", "r")
for line in input_file:
    if line.startswith('T'):
        tim = int(line.strip().split(":")[1].replace(" ", ""))
    if line.startswith('D'):
        dis = int(line.strip().split(":")[1].replace(" ", ""))
input_file.close()

wins = 0
for j in range(tim + 1):
    if (tim-j) * j > dis:
        wins += 1

print(wins)