Buggy python submission (verdict: Time Limit Exceeded):
import sys
sys.setrecursionlimit(10 ** 6)
n = int(input())
s = list(input())

from collections import defaultdict
ans = defaultdict(int)
def dfs(now, pos):
    if len(now) == 3:
        ans[now] = 1
        return
    if pos == n:
        return
    dfs(now+s[pos], pos+1)
    if ans[now] == 0:
        dfs(now, pos+1)
    ans[now] = 1

dfs("", 0)

anss = 0
for v,i in ans.items():
    if len(str(v)) == 3:
        anss += i

print(anss)


Fixed submission:
import sys
sys.setrecursionlimit(10 ** 6)
n = int(input())
s = list(input())

ans = 0
num = [str(i) for i in range(10)]
for i in num:
    for l in range(n):
        if s[l] == i:
            for j in num:
                for m in range(l+1,n):
                    if s[m] == j:
                        for k in num:
                            for p in range(m+1, n):
                                if s[p] == k:
                                    ans += 1
                                    break
                            continue
                        break
            break

print(ans)

Buggy python submission (verdict: Time Limit Exceeded):
import sys
sys.setrecursionlimit(10 ** 6)
n = int(input())
s = list(input())

from collections import defaultdict
ans = defaultdict(int)
def dfs(now, pos):
    if len(now) == 3:
        ans[now] = 1
        return
    if pos == n:
        return
    dfs(now+s[pos], pos+1)
    dfs(now, pos+1)

dfs("", 0)

anss = 0
for i in ans.values():
    anss += i

print(anss)


Fixed submission:
import sys
sys.setrecursionlimit(10 ** 6)
n = int(input())
s = list(input())

ans = 0
num = [str(i) for i in range(10)]
for i in num:
    for l in range(n):
        if s[l] == i:
            for j in num:
                for m in range(l+1,n):
                    if s[m] == j:
                        for k in num:
                            for p in range(m+1, n):
                                if s[p] == k:
                                    ans += 1
                                    break
                            continue
                        break
            break

print(ans)

Buggy python submission (verdict: Time Limit Exceeded):
import sys
sys.setrecursionlimit(10 ** 6)
n = int(input())
s = list(input())

from collections import defaultdict
ans = defaultdict(int)
def dfs(now, pos):
    if len(now) == 3:
        ans[now] = 1
        return
    if pos == n:
        return
    dfs(now+s[pos], pos+1)
    dfs(now, pos+1)

dfs("", 0)

anss = 0
for i in ans.values():
    anss += i

print(anss)


Fixed submission:
import sys
sys.setrecursionlimit(10 ** 6)
n = int(input())
s = list(input())

ans = 0
num = [str(i) for i in range(10)]
for i in num:
    for l in range(n):
        if s[l] == i:
            for j in num:
                for m in range(l+1,n):
                    if s[m] == j:
                        for k in num:
                            for p in range(m+1, n):
                                if s[p] == k:
                                    ans += 1
                                    break
                            continue
                        break
            break

print(ans)

Buggy python submission (verdict: Runtime Error):
n = int(input())
s = list(input())

from collections import defaultdict
ans = defaultdict(int)
def dfs(now, pos):
    if len(now) == 3:
        ans[now] = 1
        return
    if pos == n:
        return
    dfs(now+s[pos], pos+1)
    dfs(now, pos+1)

dfs("", 0)

anss = 0
for i in ans.values():
    anss += i

print(anss)


Fixed submission:
import sys
sys.setrecursionlimit(10 ** 6)
n = int(input())
s = list(input())

ans = 0
num = [str(i) for i in range(10)]
for i in num:
    for l in range(n):
        if s[l] == i:
            for j in num:
                for m in range(l+1,n):
                    if s[m] == j:
                        for k in num:
                            for p in range(m+1, n):
                                if s[p] == k:
                                    ans += 1
                                    break
                            continue
                        break
            break

print(ans)