Buggy python submission (verdict: Runtime Error):
#順番考えなくていいかとりあえず試す
m = int(input())
nm = [(0,0)]
for i in range(m):
    di,ci = map(int, input().split( ))
    nm.append((di,ci))
cnt = 0
tmp = 0
while nm:
    ci,di = nm.pop()
    if di>100:
        tmpy = 1
        tmpz = 1
        tmpx = ci*2
        if tmpx>=10:
            tmpx = str(tmpx)
            tmp2 = int(tmpx[0])+int(tmpx[1])
            tmpy += 1
        while tmpx != ci:
            tmpx += ci
            tmpy +=1
            tmpz +=1
            if tmpx>=10:
                tmpx = str(tmpx)
                tmp2 = int(tmpx[0])+int(tmpx[1])
                tmpy += 1
        cnt += tmpz*(di//tmpy)
        di -= (di//tmpy)*tmpy

    while di:
        cnt += 1
        #print(di,cnt)
        tmp += ci
        di-=1
        if tmp>=10:
            tmp = str(tmp)
            tmp2 = int(tmp[0])+int(tmp[1])
            cnt += 1
            #print(di,cnt)
            tmp = tmp2
print(cnt-1)
    

Fixed submission:
#繰り上がりごとに各桁の総和は9減る
#9*最初の桁数+最初の総和がそれで減る
#それは順番によらない

m = int(input())
sm=  0
d = []
c = []
for i in range(m):
    di,ci = map(int, input().split( ))
    d.append(di)
    c.append(ci)
    sm += di*ci

x = sum(c)*9 + sm
y =  x%9
if y==0:
    y = 9
    
print((x-y)//9-1)

Buggy python submission (verdict: Runtime Error):
#順番考えなくていいかとりあえず試す
m = int(input())
nm = []
for i in range(m):
    di,ci = map(int, input().split( ))
    nm.append((di,ci))
cnt = 0
tmp = 0
while nm:
    ci,di = nm.pop()
    if di>100:
        tmpy = 1
        tmpz = 1
        tmpx = ci*2
        if tmpx>=10:
            tmpx = str(tmpx)
            tmp2 = int(tmpx[0])+int(tmpx[1])
            tmpy += 1
        while tmpx != ci:
            tmpx += ci
            tmpy +=1
            tmpz +=1
            if tmpx>=10:
                tmpx = str(tmpx)
                tmp2 = int(tmpx[0])+int(tmpx[1])
                tmpy += 1
        cnt += tmpz*(di//tmpy)
        di -= (di//tmpy)*tmpy

    while di:
        cnt += 1
        #print(di,cnt)
        tmp += ci
        di-=1
        if tmp>=10:
            tmp = str(tmp)
            tmp2 = int(tmp[0])+int(tmp[1])
            cnt += 1
            #print(di,cnt)
            tmp = tmp2
print(cnt-1)
    

Fixed submission:
#繰り上がりごとに各桁の総和は9減る
#9*最初の桁数+最初の総和がそれで減る
#それは順番によらない

m = int(input())
sm=  0
d = []
c = []
for i in range(m):
    di,ci = map(int, input().split( ))
    d.append(di)
    c.append(ci)
    sm += di*ci

x = sum(c)*9 + sm
y =  x%9
if y==0:
    y = 9
    
print((x-y)//9-1)

Buggy python submission (verdict: Runtime Error):
#順番考えなくていいかとりあえず試す
m = int(input())
nm = []
for i in range(m):
    di,ci = map(int, input().split( ))
    nm.append((di,ci))
cnt = 0
tmp = 0
while nm:
    ci,di = nm.pop()
    if di>100:
        tmpy = 1
        tmpz = 1
        tmpx = ci*2
        if tmpx>=10:
            tmpx = str(tmpx)
            tmp2 = int(tmpx[0])+int(tmpx[1])
            tmpy += 1
        while tmpx != ci:
            tmpx += ci
            tmpy +=1
            tmpz +=1
            if tmpx>=10:
                tmpx = str(tmpx)
                tmp2 = int(tmpx[0])+int(tmpx[1])
                tmpy += 1
        tmp += tmpz*(di//tmpy)
        di -= (di//tmpy)*tmpy

    while di:
        cnt += 1
        #print(di,cnt)
        tmp += ci
        di-=1
        if tmp>=10:
            tmp = str(tmp)
            tmp2 = int(tmp[0])+int(tmp[1])
            cnt += 1
            #print(di,cnt)
            tmp = tmp2
print(cnt-1)
    

Fixed submission:
#繰り上がりごとに各桁の総和は9減る
#9*最初の桁数+最初の総和がそれで減る
#それは順番によらない

m = int(input())
sm=  0
d = []
c = []
for i in range(m):
    di,ci = map(int, input().split( ))
    d.append(di)
    c.append(ci)
    sm += di*ci

x = sum(c)*9 + sm
y =  x%9
if y==0:
    y = 9
    
print((x-y)//9-1)

Buggy python submission (verdict: Time Limit Exceeded):
#順番考えなくていいかとりあえず試す
#配列をタプルに変更
m = int(input())
nm = []
for i in range(m):
    di,ci = map(int, input().split( ))
    nm.append((di,ci))
cnt = 0
tmp = 0
while nm:
    ci,di = nm.pop()
    while di:
        cnt += 1
        #print(di,cnt)
        tmp += ci
        di-=1
        if tmp>=10:
            tmp = str(tmp)
            tmp2 = int(tmp[0])+int(tmp[1])
            cnt += 1
            #print(di,cnt)
            tmp = tmp2
print(cnt-1)
    

Fixed submission:
#繰り上がりごとに各桁の総和は9減る
#9*最初の桁数+最初の総和がそれで減る
#それは順番によらない

m = int(input())
sm=  0
d = []
c = []
for i in range(m):
    di,ci = map(int, input().split( ))
    d.append(di)
    c.append(ci)
    sm += di*ci

x = sum(c)*9 + sm
y =  x%9
if y==0:
    y = 9
    
print((x-y)//9-1)

Buggy python submission (verdict: Time Limit Exceeded):
#順番考えなくていいかとりあえず試す
m = int(input())
nm = []
for i in range(m):
    di,ci = map(int, input().split( ))
    nm.append([di,ci])
cnt = 0
tmp = 0
while nm:
    ci,di = nm.pop()
    while di:
        cnt += 1
        #print(di,cnt)
        tmp += ci
        di-=1
        if tmp>=10:
            tmp = str(tmp)
            tmp2 = int(tmp[0])+int(tmp[1])
            cnt += 1
            #print(di,cnt)
            tmp = tmp2
print(cnt-1)
    

Fixed submission:
#繰り上がりごとに各桁の総和は9減る
#9*最初の桁数+最初の総和がそれで減る
#それは順番によらない

m = int(input())
sm=  0
d = []
c = []
for i in range(m):
    di,ci = map(int, input().split( ))
    d.append(di)
    c.append(ci)
    sm += di*ci

x = sum(c)*9 + sm
y =  x%9
if y==0:
    y = 9
    
print((x-y)//9-1)