复杂度 $O(n)$，莫名RE+TLE

def main():

    n = int(input())
    
    s = input()
    
    a = [0] * (n + 2)
    
    f = [0] * (n + 2)

    f[0] = 1
    
    for i in range(1, n+1):
        f[i] = f[i - 1] * 10


    for i in range(0, n):
        x = s[i]
        a[i+1] = int(x)

    ans = 0

    for i in range(1, n + 1):
        term = (f[n - i + 1] - 1) // 9
        term *= a[i]
        term *= i
        ans += term

    print(ans)
    
if __name__ == "__main__":
    main()