#!/usr/bin/env pypy3

import array


def minimum_number_of_operations(n, xs):
    if n == 1:
        return 0
    else:
        return sum(1 for i in range(1, n) if xs[i] <= xs[i - 1])


def main():
    n = int(input())
    xs = array.array("L", map(int, input().split()))
    print(minimum_number_of_operations(n, xs))


if __name__ == '__main__':
    main()