#!/usr/bin/env python3

def modpw(n, p):
    r = 0
    while n >= p:
        r += n // p
        n //= p
    return r

n = 10**8 + 1
sieve = [0] * n

for p in range(2, n):
    if sieve[p] > 0:
        continue
    minN = p
    frompw = 1
    topw   = 2
    k = 1
    while k*p < n:
        for pw in range(frompw, topw):
            k *= p
            for m in range(k, n, k):
                sieve[m] = max(sieve[m], minN)
        minN += p
        frompw = topw
        topw   = modpw(minN, p) + 1

print(sum(sieve[2:]))