Buggy python submission (verdict: Runtime Error):
X=list(map(int,input().split()))
#X軸に並行
if X[2]-X[0]==0:
    if X[3]-X[1]>0:
        q=X[3]-X[1]
        U="U"
        D="D"
    else:
        q=X[1]-X[3]
        U="U"
        D="D"
    print(U*(q+1)+R*2+D*(q+2)+L*2+U+L+U*q+R*2+D*q+L)
#Y軸に並行
if X[3]-X[1]==0:
    if X[2]-X[0]>0:
        p=X[2]-X[0]
        R="R"
        L="L"
    else:
        p=X[0]-X[2]
        R="L"
        L="R"
    print(R*(p+1)+U*2+L*(p+2)+D*2+R+D+R*p+U*2+L*p+D)

if X[2]-X[0]!=0 and X[3]-X[1]!=0
    if X[2]-X[0]>0:
        p=X[2]-X[0]
        R="R"
        L="L"
    else:
        p=X[0]-X[2]
        R="L"
        L="R"
    if X[3]-X[1]>0:
        q=X[3]-X[1]
        U="U"
        D="D"
    else:
        q=X[1]-X[3]
        U="D"
        D="U"
    print(U*p+R*(q+1)+D*(p+1)+L*(q+1)+U+L+U*(p+1)+R*(q+1)+D*(p+1)+L*q)  

Fixed submission:
sx, sy, tx, ty = map(int, input().split())

higth = ty - sy
width = tx - sx

ans = ''
ans += 'U' * higth
ans += 'R' * width
ans += 'D' * higth
ans += 'L' * width
ans += 'L' + 'U' * (higth + 1)
ans += 'R' * (width + 1) + 'D'
ans += 'R' + 'D' * (higth + 1)
ans += 'L' * (width + 1) + 'U'
print(ans)

Buggy python submission (verdict: Runtime Error):
X=list(map(int,input().split()))
#X軸に並行
if X[2]-X[0]==0:
    if X[3]-X[1]>0:
        q=X[3]-X[1]
        U="U"
        D="D"
    else:
        q=X[1]-X[3]
        U="U"
        D="D"
    print(U*(q+1)+R*2+D*(q+2)+L*2+U+L+U*q+R*2+D*q+L)
#Y軸に並行
if X[3]-X[1]==0:
    if X[2]-X[0]>0:
        p=X[2]-X[0]
        R="R"
        L="L"
    else:
        p=X[0]-X[2]
        R="L"
        L="R"
    print(R*(p+1)+U*2+L*(p+2)+D*2+R+D+R*p+U*2+L*p+D)

if X[2]-X[0]!=0 or X[3]-X[1]!=0
    if X[2]-X[0]>0:
        p=X[2]-X[0]
        R="R"
        L="L"
    else:
        p=X[0]-X[2]
        R="L"
        L="R"
    if X[3]-X[1]>0:
        q=X[3]-X[1]
        U="U"
        D="D"
    else:
        q=X[1]-X[3]
        U="D"
        D="U"
    print(U*p+R*(q+1)+D*(p+1)+L*(q+1)+U+L+U*(p+1)+R*(q+1)+D*(p+1)+L*q)  

Fixed submission:
sx, sy, tx, ty = map(int, input().split())

higth = ty - sy
width = tx - sx

ans = ''
ans += 'U' * higth
ans += 'R' * width
ans += 'D' * higth
ans += 'L' * width
ans += 'L' + 'U' * (higth + 1)
ans += 'R' * (width + 1) + 'D'
ans += 'R' + 'D' * (higth + 1)
ans += 'L' * (width + 1) + 'U'
print(ans)

Buggy python submission (verdict: Runtime Error):
X=list(map(int.input().split()))
if X[2]-X[0]>0:
    p=X[2]-X[0]
    U="U"
    D="D"
else:
    p=X[0]-X[2]
    U="D"
    D="U"

if X[3]-X[1]>0:
    q=X[3]-X[1]
    R="R"
    L="L"
else:
    q=X[1]-X[3]
    R="L"
    L="R"
    
print(U*p+R*(q+1)+D*(p+1)+L*(q+1)+U+L+U*(p+1)+R*(q+1)+D*(p+1)+L*q)  

Fixed submission:
sx, sy, tx, ty = map(int, input().split())

higth = ty - sy
width = tx - sx

ans = ''
ans += 'U' * higth
ans += 'R' * width
ans += 'D' * higth
ans += 'L' * width
ans += 'L' + 'U' * (higth + 1)
ans += 'R' * (width + 1) + 'D'
ans += 'R' + 'D' * (higth + 1)
ans += 'L' * (width + 1) + 'U'
print(ans)

Buggy python submission (verdict: Runtime Error):
X=list(map(int.input().split()))
ans=""
if X[2]-X[0]>0:
    p=X[2]-X[0]
    U="U"
    D="D"
else:
    p=X[0]-X[2]
    U="D"
    D="U"

if X[3]-X[1]>0:
    q=X[3]-X[1]
    R="R"
    L="L"
else:
    q=X[1]-X[3]
    R="L"
    L="R"
    
print(U*p+R*(q+1)+D*(p+1)+L*(q+1)+U+L+U*(p+1)+R*(q+1)+D*(p+1)+L*q  

Fixed submission:
sx, sy, tx, ty = map(int, input().split())

higth = ty - sy
width = tx - sx

ans = ''
ans += 'U' * higth
ans += 'R' * width
ans += 'D' * higth
ans += 'L' * width
ans += 'L' + 'U' * (higth + 1)
ans += 'R' * (width + 1) + 'D'
ans += 'R' + 'D' * (higth + 1)
ans += 'L' * (width + 1) + 'U'
print(ans)