Buggy python submission (verdict: Time Limit Exceeded):
n = int(input())
s = input()
ans = 0

for i in range(0,1000):
    num = str(i)
    if i < 10:
        num = "00"+num
    elif i <100:
        num = "0" + num
    f = 0
    for j in range(n):
        if s[j] == num[f]:
            f += 1
        if f == 3:
            break
    if f==3:
        ans +=1
print(ans)
                        


Fixed submission:
n = int(input())
s = input()
ans = 0

for i in range(0,1000):
    num = str(i)
    if i < 10:
        num = "00"+num
    elif i <100:
        num = "0" + num
    f = 0
    for j in range(n):
        if s[j] == num[f]:
            f += 1
        if f == 3:
            break
    if f==3:
        ans +=1
print(ans)

Buggy python submission (verdict: Time Limit Exceeded):
n = int(input())
s = input()
ans = set()

for i in range(0,1000):
    flag = False
    num = str(i)
    if i < 10:
        num = "00"+num
    elif i <100:
        num = "0" + num
    for j in range(n):
        if s[j] == num[0]:
            for k in range(j+1,n):
                if s[k] == num[1]:
                    for l in range(k+1,n):
                        if s[l] == num[2]:
                            flag = True
                            ans.add(i)
                if flag:
                    break
        if flag:
            break
print(len(ans))
                        

Fixed submission:
n = int(input())
s = input()
ans = 0

for i in range(0,1000):
    num = str(i)
    if i < 10:
        num = "00"+num
    elif i <100:
        num = "0" + num
    f = 0
    for j in range(n):
        if s[j] == num[f]:
            f += 1
        if f == 3:
            break
    if f==3:
        ans +=1
print(ans)

Buggy python submission (verdict: Time Limit Exceeded):
def I(): return int(input())
def LI(): return list(map(int,input().split()))
def MI(): return map(int,input().split())
def LLI(n): return [list(map(int, input().split())) for _ in range(n)]


n = int(input())
s = input()
ans = set()

for i in range(0,1000):
  b = 1
  num = str(i)
  if i < 10:
    num = "00"+num
  elif i <100:
    num = "0" + num
  for j in range(n):
    if b == 0:
      break
    if s[j] == num[0]:
      for k in range(j+1,n):
        if b == 0:
          break
        if s[k] == num[1]:
          for l in range(k+1,n):
            if b == 0:
              break
            if s[l] == num[2]:
              ans.add(i)
              b = 0
print(len(ans))
                        


Fixed submission:
n = int(input())
s = input()
ans = 0

for i in range(0,1000):
    num = str(i)
    if i < 10:
        num = "00"+num
    elif i <100:
        num = "0" + num
    f = 0
    for j in range(n):
        if s[j] == num[f]:
            f += 1
        if f == 3:
            break
    if f==3:
        ans +=1
print(ans)

Buggy python submission (verdict: Time Limit Exceeded):
def I(): return int(input())
def LI(): return list(map(int,input().split()))
def MI(): return map(int,input().split())
def LLI(n): return [list(map(int, input().split())) for _ in range(n)]


n = int(input())
s = input()
ans = set()

for i in range(0,1000):
    num = str(i)
    if i < 10:
        num = "00"+num
    elif i <100:
        num = "0" + num
    for j in range(n):
        if s[j] == num[0]:
            for k in range(j+1,n):
                if s[k] == num[1]:
                    for l in range(k+1,n):
                        if s[l] == num[2]:
                            ans.add(i)
print(len(ans))
                        

Fixed submission:
n = int(input())
s = input()
ans = 0

for i in range(0,1000):
    num = str(i)
    if i < 10:
        num = "00"+num
    elif i <100:
        num = "0" + num
    f = 0
    for j in range(n):
        if s[j] == num[f]:
            f += 1
        if f == 3:
            break
    if f==3:
        ans +=1
print(ans)

Buggy python submission (verdict: Time Limit Exceeded):
def I(): return int(input())
def LI(): return list(map(int,input().split()))
def MI(): return map(int,input().split())
def LLI(n): return [list(map(int, input().split())) for _ in range(n)]


n = int(input())
s = input()
ans = set()

for i in range(0,1000):
    num = str(i)
    if i < 10:
        num = "00"+num
    elif i <100:
        num = "0" + num
    for j in range(n):
        if s[j] == num[0]:
            for k in range(j+1,n):
                if s[k] == num[1]:
                    for l in range(k+1,n):
                        if s[l] == num[2]:
                            ans.add(i)
print(len(ans))
                        

Fixed submission:
n = int(input())
s = input()
ans = 0

for i in range(0,1000):
    num = str(i)
    if i < 10:
        num = "00"+num
    elif i <100:
        num = "0" + num
    f = 0
    for j in range(n):
        if s[j] == num[f]:
            f += 1
        if f == 3:
            break
    if f==3:
        ans +=1
print(ans)