Buggy python submission (verdict: Runtime Error):
a=input()
a_l=len(a)
b=input()
b_l=len(b)
c=input()
c_l=len(c)
def check(s1,s2):
    l1=len(s1)
    l2=len(s2)
    ret=[0]*(l1+l2-1)
    for i in range(l1+l2-1):
        flag=True
        if i-l2+1<0:
            for j in range(i+1):
                if s1[j]!="?" and s2[l2-i+j-1]!="?" and s1[j]!=s2[l2-i+j-1]:
                    flag=False
                    break
        elif i-l2+1>=0 and i<=l1-1:
            for j in range(l2):
                if s1[i-l2+j+1]!="?" and s2[j]!="?" and s1[i-l2+j+1]!=s2[j]:
                    flag=False
                    break
        else:
            for j in range(l1+l2-i-1):
                if s1[i-l2+j+1]!="?" and s2[j]!="?" and s1[i-l2+j+1]!=s2[j]:
                    flag=False
                    break
        ret[i]=flag
    return ret
ab=check(a,b)
ab_l=len(ab)
ac=check(a,c)
ac_l=len(ac)
bc=check(b,c)
bc_l=len(bc)
ans=a_l+b_l+c_l
for i in range(-2000,ab_l+2000):
    if i<0 or i>=ab_l or ab[i]:
        for j in range(-2000,ac_l+2000):
            if j<0 or j>=ac_l or ac[j]:
                if j-i+b_l+1<0 or j-i+b_l+1>=bc_l or bc[j-i+b_l+1]:
                    l=max(a_l-1,i,j)-min(0,i-b_l+1,j-c_l+1)+1
                    ans=min(ans,l)
print(ans)

Fixed submission:
a=input()
a_l=len(a)
b=input()
b_l=len(b)
c=input()
c_l=len(c)
def check(s1,s2):
    l1=len(s1)
    l2=len(s2)
    ret=[0]*(l1+l2-1)
    for i in range(l1+l2-1):
        flag=True
        if i-l2+1<0 and i<=l1-1:
            for j in range(i+1):
                if s1[j]!="?" and s2[l2-i+j-1]!="?" and s1[j]!=s2[l2-i+j-1]:
                    flag=False
                    break
        elif i-l2+1<0 and i>l1-1:
            for j in range(l1):
                if s1[j]!="?" and s2[l2-i+j-1]!="?" and s1[j]!=s2[l2-i+j-1]:
                    flag=False
                    break
        elif i-l2+1>=0 and i<=l1-1:
            for j in range(l2):
                if s1[i-l2+j+1]!="?" and s2[j]!="?" and s1[i-l2+j+1]!=s2[j]:
                    flag=False
                    break
        else:
            for j in range(l1+l2-i-1):
                if s1[i-l2+j+1]!="?" and s2[j]!="?" and s1[i-l2+j+1]!=s2[j]:
                    flag=False
                    break
        ret[i]=flag
    return ret
ab=check(a,b)
ab_l=len(ab)
ac=check(a,c)
ac_l=len(ac)
bc=check(b,c)
bc_l=len(bc)
ans=a_l+b_l+c_l
for i in range(-2000,ab_l+2000):
    if i<0 or i>=ab_l or ab[i]:
        for j in range(-2000,ac_l+2000):
            if j<0 or j>=ac_l or ac[j]:
                if j-i+b_l-1<0 or j-i+b_l-1>=bc_l or bc[j-i+b_l-1]:
                    l=max(a_l-1,i,j)-min(0,i-b_l+1,j-c_l+1)+1
                    ans=min(ans,l)
print(ans)

Buggy python submission (verdict: Runtime Error):
a=input()
a_l=len(a)
b=input()
b_l=len(b)
c=input()
c_l=len(c)
def check(s1,s2):
    l1=len(s1)
    l2=len(s2)
    ret=[0]*(l1+l2-1)
    for i in range(l1+l2-1):
        flag=True
        if i-l2+1<0:
            for j in range(i+1):
                if s1[j]!="?" and s2[l2-i+j-1]!="?" and s1[j]!=s2[l2-i+j-1]:
                    flag=False
                    break
        elif i-l2+1>=0 and i<=l1-1:
            for j in range(l2):
                if s1[i-l2+j+1]!="?" and s2[j]!="?" and s1[i-l2+j+1]!=s2[j]:
                    flag=False
                    break
        else:
            for j in range(l1+l2-i-1):
                if s1[i-l2+j+1]!="?" and s2[j]!="?" and s1[i-l2+j+1]!=s2[j]:
                    flag=False
                    break
        ret[i]=flag
    return ret
ab=check(a,b)
ab_l=len(ab)
ac=check(a,c)
ac_l=len(ac)
bc=check(b,c)
bc_l=len(bc)
ans=a_l+b_l+c_l
for i in range(-3000,ab_l+3000):
    if i<0 or i>=ab_l or ab[i]:
        for j in range(-3000,ac_l+3000):
            if j<0 or j>=ac_l or ac[j]:
                if (0<=j-i+b_l+1<bc_l and bc[j-i+b_l+1]) or j-i+b_l+1<0 or j-i+b_l+1>=bc_l:
                    l=max(a_l-1,i,j)-min(0,i-b_l+1,j-c_l+1)+1
                    ans=min(ans,l)
print(ans)

Fixed submission:
a=input()
a_l=len(a)
b=input()
b_l=len(b)
c=input()
c_l=len(c)
def check(s1,s2):
    l1=len(s1)
    l2=len(s2)
    ret=[0]*(l1+l2-1)
    for i in range(l1+l2-1):
        flag=True
        if i-l2+1<0 and i<=l1-1:
            for j in range(i+1):
                if s1[j]!="?" and s2[l2-i+j-1]!="?" and s1[j]!=s2[l2-i+j-1]:
                    flag=False
                    break
        elif i-l2+1<0 and i>l1-1:
            for j in range(l1):
                if s1[j]!="?" and s2[l2-i+j-1]!="?" and s1[j]!=s2[l2-i+j-1]:
                    flag=False
                    break
        elif i-l2+1>=0 and i<=l1-1:
            for j in range(l2):
                if s1[i-l2+j+1]!="?" and s2[j]!="?" and s1[i-l2+j+1]!=s2[j]:
                    flag=False
                    break
        else:
            for j in range(l1+l2-i-1):
                if s1[i-l2+j+1]!="?" and s2[j]!="?" and s1[i-l2+j+1]!=s2[j]:
                    flag=False
                    break
        ret[i]=flag
    return ret
ab=check(a,b)
ab_l=len(ab)
ac=check(a,c)
ac_l=len(ac)
bc=check(b,c)
bc_l=len(bc)
ans=a_l+b_l+c_l
for i in range(-2000,ab_l+2000):
    if i<0 or i>=ab_l or ab[i]:
        for j in range(-2000,ac_l+2000):
            if j<0 or j>=ac_l or ac[j]:
                if j-i+b_l-1<0 or j-i+b_l-1>=bc_l or bc[j-i+b_l-1]:
                    l=max(a_l-1,i,j)-min(0,i-b_l+1,j-c_l+1)+1
                    ans=min(ans,l)
print(ans)