Buggy python submission (verdict: Time Limit Exceeded):
import sys
from math import ceil, floor, sqrt, sin, cos, pi
from itertools import accumulate, permutations, combinations
from fractions import gcd # 最大公約数
from collections import deque, Counter
from operator import itemgetter
from heapq import heappop,heappush
sys.setrecursionlimit(10**7)
def lcm(x, y): return ((x * y) // gcd(x, y)) # 最小公倍数
# list(map(int, input().split()))
# map(int, input().split())
# int(input())
# input().split()
# mojiretu = ','.join(str_list)
# sorted(input())

n = int(input())
t = input()
p = t[0]
ans = 0
s = t[0]
# 連続4文字以上を圧縮
for x in t[1:]:
    if x == p:
        ans += 1
        if ans < 4:
            s += x
    else:
        ans = 1
        s += x

ans = 0
for t in range(1000):
    q = str(int(t/100))
    if not q in s:
        continue
    z = s.index(q) + 1
    p = deque([int((t%100 - t%10)/10), t%10, -1])
    q = p.popleft()
    for x in s[z:]:
        if q == int(x):
            q = p.popleft()
        if q == -1:
            ans += 1
            break
    else:
        if q == -1:
            ans += 1
print(ans)


Fixed submission:
import sys
from math import ceil, floor, sqrt, sin, cos, pi
from itertools import accumulate, permutations, combinations
from fractions import gcd # 最大公約数
from collections import deque, Counter
from operator import itemgetter
from heapq import heappop,heappush
sys.setrecursionlimit(10**7)
def lcm(x, y): return ((x * y) // gcd(x, y)) # 最小公倍数
# list(map(int, input().split()))
# map(int, input().split())
# int(input())
# input().split()
# mojiretu = ','.join(str_list)
# sorted(input())

n = int(input())
s = input()
cnt = 0
q = s[0]
t = s[0]
for x in s[1:]:
    if x == q:
        cnt += 1
        if cnt < 3:
            t += x
    else:
        cnt = 0
        t += x
        q = x
ans = 0
for i in range(10):
    x = t.find(str(i)) + 1
    if not x: continue
    for j in range(10):
        y = t[x:].find(str(j)) + 1
        if not y: continue
        for k in range(10):
            z = t[x + y:].find(str(k)) + 1
            if not z: continue
            #print(i,j,k, ':', x,y,z)
            ans += 1
print(ans)

Buggy python submission (verdict: Time Limit Exceeded):
import sys
from math import ceil, floor, sqrt, sin, cos, pi
from itertools import accumulate, permutations, combinations
from fractions import gcd # 最大公約数
from collections import deque, Counter
from operator import itemgetter
from heapq import heappop,heappush
sys.setrecursionlimit(10**7)
def lcm(x, y): return ((x * y) // gcd(x, y)) # 最小公倍数
# list(map(int, input().split()))
# map(int, input().split())
# int(input())
# input().split()
# mojiretu = ','.join(str_list)
# sorted(input())

n = int(input())
s = input()

ans = 0
for t in range(1000):
    q = str(int(t/100))
    if not q in s:
        continue
    z = s.index(q) + 1
    p = deque([int((t%100 - t%10)/10), t%10, -1])
    q = p.popleft()
    for x in s[z:]:
        if q == -1:
            ans += 1
            break
        if q == int(x):
            q = p.popleft()
    else:
        if q == -1:
            ans += 1
print(ans)


Fixed submission:
import sys
from math import ceil, floor, sqrt, sin, cos, pi
from itertools import accumulate, permutations, combinations
from fractions import gcd # 最大公約数
from collections import deque, Counter
from operator import itemgetter
from heapq import heappop,heappush
sys.setrecursionlimit(10**7)
def lcm(x, y): return ((x * y) // gcd(x, y)) # 最小公倍数
# list(map(int, input().split()))
# map(int, input().split())
# int(input())
# input().split()
# mojiretu = ','.join(str_list)
# sorted(input())

n = int(input())
s = input()
cnt = 0
q = s[0]
t = s[0]
for x in s[1:]:
    if x == q:
        cnt += 1
        if cnt < 3:
            t += x
    else:
        cnt = 0
        t += x
        q = x
ans = 0
for i in range(10):
    x = t.find(str(i)) + 1
    if not x: continue
    for j in range(10):
        y = t[x:].find(str(j)) + 1
        if not y: continue
        for k in range(10):
            z = t[x + y:].find(str(k)) + 1
            if not z: continue
            #print(i,j,k, ':', x,y,z)
            ans += 1
print(ans)

Buggy python submission (verdict: Time Limit Exceeded):
import sys
from math import ceil, floor, sqrt, sin, cos, pi
from itertools import accumulate, permutations, combinations
from fractions import gcd # 最大公約数
from collections import deque, Counter
from operator import itemgetter
from heapq import heappop,heappush
sys.setrecursionlimit(10**7)
def lcm(x, y): return ((x * y) // gcd(x, y)) # 最小公倍数
# list(map(int, input().split()))
# map(int, input().split())
# int(input())
# input().split()
# mojiretu = ','.join(str_list)
# sorted(input())

n = int(input())
s = input()

ans = 0
for t in range(1000):
    p = deque([int(t/100), int((t%100 - t%10)/10), t%10, -1])
    q = p.popleft()
    for x in s:
        if q == -1:
            ans += 1
            break
        if q == int(x):
            q = p.popleft()
    else:
        if q == -1: ans += 1
print(ans)


Fixed submission:
import sys
from math import ceil, floor, sqrt, sin, cos, pi
from itertools import accumulate, permutations, combinations
from fractions import gcd # 最大公約数
from collections import deque, Counter
from operator import itemgetter
from heapq import heappop,heappush
sys.setrecursionlimit(10**7)
def lcm(x, y): return ((x * y) // gcd(x, y)) # 最小公倍数
# list(map(int, input().split()))
# map(int, input().split())
# int(input())
# input().split()
# mojiretu = ','.join(str_list)
# sorted(input())

n = int(input())
s = input()
cnt = 0
q = s[0]
t = s[0]
for x in s[1:]:
    if x == q:
        cnt += 1
        if cnt < 3:
            t += x
    else:
        cnt = 0
        t += x
        q = x
ans = 0
for i in range(10):
    x = t.find(str(i)) + 1
    if not x: continue
    for j in range(10):
        y = t[x:].find(str(j)) + 1
        if not y: continue
        for k in range(10):
            z = t[x + y:].find(str(k)) + 1
            if not z: continue
            #print(i,j,k, ':', x,y,z)
            ans += 1
print(ans)