Buggy python submission (verdict: Runtime Error):

# Author: cr4zjh0bp
# Created: Sun Mar  8 11:28:28 UTC 2020
import sys
 
stdin = sys.stdin
inf = 1 << 60
mod = 1000000007
 
ni = lambda: int(ns())
nin = lambda y: [ni() for _ in range(y)]
na = lambda: list(map(int, stdin.readline().split()))
nan = lambda y: [na() for _ in range(y)]
nf = lambda: float(ns())
nfn = lambda y: [nf() for _ in range(y)]
nfa = lambda: list(map(float, stdin.readline().split()))
nfan = lambda y: [nfa() for _ in range(y)]
ns = lambda: stdin.readline().rstrip()
nsn = lambda y: [ns() for _ in range(y)]
ncl = lambda y: [list(ns()) for _ in range(y)]
nas = lambda: stdin.readline().split()

s = ns()
n = len(s)
cnt = True
i = 0
flag = True
if n == 1:
    print("No")
else:
    while i < n:
        if s[i] != 'h' or s[i + 1] != 'i':
            flag = False
            break
        i += 2

    if flag:
        print("Yes")
    else:
        print("No")


Fixed submission:
# Author: cr4zjh0bp
# Created: Sun Mar  8 12:16:38 UTC 2020
import sys
 
stdin = sys.stdin
inf = 1 << 60
mod = 1000000007
 
ni = lambda: int(ns())
nin = lambda y: [ni() for _ in range(y)]
na = lambda: list(map(int, stdin.readline().split()))
nan = lambda y: [na() for _ in range(y)]
nf = lambda: float(ns())
nfn = lambda y: [nf() for _ in range(y)]
nfa = lambda: list(map(float, stdin.readline().split()))
nfan = lambda y: [nfa() for _ in range(y)]
ns = lambda: stdin.readline().rstrip()
nsn = lambda y: [ns() for _ in range(y)]
ncl = lambda y: [list(ns()) for _ in range(y)]
nas = lambda: stdin.readline().split()

s = ns()
n = len(s)
if n % 2 == 1:
    print("No")
else:
    i = 0
    cnt = 0
    while i < n - 1:
        if s[i] == 'h' and s[i + 1] == 'i':
            cnt += 2
        i += 2
    if cnt == n:
        print("Yes")
    else:
        print("No")

Buggy python submission (verdict: Runtime Error):
# Author: cr4zjh0bp
# Created: Sun Mar  8 11:28:28 UTC 2020
import sys
 
stdin = sys.stdin
inf = 1 << 60
mod = 1000000007
 
ni = lambda: int(ns())
nin = lambda y: [ni() for _ in range(y)]
na = lambda: list(map(int, stdin.readline().split()))
nan = lambda y: [na() for _ in range(y)]
nf = lambda: float(ns())
nfn = lambda y: [nf() for _ in range(y)]
nfa = lambda: list(map(float, stdin.readline().split()))
nfan = lambda y: [nfa() for _ in range(y)]
ns = lambda: stdin.readline().rstrip()
nsn = lambda y: [ns() for _ in range(y)]
ncl = lambda y: [list(ns()) for _ in range(y)]
nas = lambda: stdin.readline().split()

s = ns()
n = len(s)
cnt = True
i = 0
flag = True
while i < n:
    if s[i] != 'h' or s[i + 1] != 'i':
        flag = False
        break
    i += 2

if flag:
    print("Yes")
else:
    print("No")

Fixed submission:
# Author: cr4zjh0bp
# Created: Sun Mar  8 12:16:38 UTC 2020
import sys
 
stdin = sys.stdin
inf = 1 << 60
mod = 1000000007
 
ni = lambda: int(ns())
nin = lambda y: [ni() for _ in range(y)]
na = lambda: list(map(int, stdin.readline().split()))
nan = lambda y: [na() for _ in range(y)]
nf = lambda: float(ns())
nfn = lambda y: [nf() for _ in range(y)]
nfa = lambda: list(map(float, stdin.readline().split()))
nfan = lambda y: [nfa() for _ in range(y)]
ns = lambda: stdin.readline().rstrip()
nsn = lambda y: [ns() for _ in range(y)]
ncl = lambda y: [list(ns()) for _ in range(y)]
nas = lambda: stdin.readline().split()

s = ns()
n = len(s)
if n % 2 == 1:
    print("No")
else:
    i = 0
    cnt = 0
    while i < n - 1:
        if s[i] == 'h' and s[i + 1] == 'i':
            cnt += 2
        i += 2
    if cnt == n:
        print("Yes")
    else:
        print("No")