This submission is migrated from previous version of oj.uz, which used different machine for grading. This submission may have different result if resubmitted.
#include <bits/stdc++.h>
using namespace std;
#define ll long long
string fguy, sguy;
vector<int> fn, sn;
vector<int> fsub, ssub;
void inc(vector<int>& cur) {
	for (int i = cur.size()-1; i >= 0; i--) {
		if (cur[i] == 0) {
			cur[i] = 1;
			break;
		}
		else cur[i] = 0;
	}
}
int getlast(vector<int>& cur) {
	return cur[cur.size()-1];
}
vector<int> subvec(vector<int> a, vector<int> b) {
	//returns a vector, assumes same length
	bool hascarry = false;
	for (int i = a.size()-1; i >= 0; i--) {
		if (hascarry) {
			a[i]--;
			hascarry = false;
		}
		a[i] -= b[i];
		if (a[i] < 0) {
			a[i] += 2;
			hascarry = true;
		}
	}
	return a;
}
ll getval(vector<int>& cur) {
	if (cur.size() > 19) {
		return 1000000000;
	}
	ll ans = 0;
	for (int i = 0; i < cur.size(); i++) {
		ans *= 2LL;
		ans += cur[i] + 0LL;
	}
	return ans;
}
string printvect(vector<int>& guy) {
	string res = "";
	for (int i = 0; i < guy.size(); i++) {
		res += to_string(guy[i]);
	}
	return res;
}
int main() {
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);
	cin >> fguy >> sguy;
	fn.push_back(1);
	sn.push_back(1);
	fsub.push_back(0);
	ssub.push_back(0);
	ll ans = 1000000000;
	for (int i = 0; i < fguy.length(); ++i) {
		if (fguy[i] == '1') {
			fn.push_back(0);
			fsub.push_back(0);
		}
		if (fguy[i] == '2') {
			fn.push_back(1);
			fsub.push_back(0);
		}
		if (fguy[i] == 'U') {
			if (getlast(fsub) == 1) {
				if (getlast(fn) != 1) {
					inc(fsub);
				}
			}
			fn.pop_back();
			fsub.pop_back();
		}
		if (fguy[i] == 'L') {
			inc(fsub);
		}
		if (fguy[i] == 'R') {
			inc(fn);
		}
	}
	for (int i = 0; i < sguy.length(); ++i) {
		if (sguy[i] == '1') {
			sn.push_back(0);
			ssub.push_back(0);
		}
		if (sguy[i] == '2') {
			sn.push_back(1);
			ssub.push_back(0);
		}
		if (sguy[i] == 'U') {
			if (getlast(ssub) == 1) {
				if (getlast(sn) != 1) {
					inc(ssub);
				}
			}
			sn.pop_back();
			ssub.pop_back();
		}
		if (sguy[i] == 'L') {
			inc(ssub);
		}
		if (sguy[i] == 'R') {
			inc(sn);
		}
	}
	fn = subvec(fn, fsub);
	sn = subvec(sn, ssub);
	// cout << "fn: " << printvect(fn) << " " << getval(fn) << endl;
	// cout << "sn: " << printvect(sn) << " " << getval(sn) << endl;
	// cout << endl;
	ll cans = 0;
	while (fn.size() > sn.size()) {
		fn.pop_back();
		cans++;
	}
	while (sn.size() > fn.size()) {
		sn.pop_back();
		cans++;
	}
	bool sngreater = false;
	for (int i = 0; i < fn.size(); i++) {
		if (fn[i] > sn[i]) break;
		if (sn[i] > fn[i]) {
			sngreater = true;
			break;
		}
	}
	if (sngreater) {
		fn.swap(sn);
	}
	ll cdiff = 0LL;
	for (int i = 0; i < fn.size() && cdiff <= 300000; i++) {
		cdiff *= 2LL;
		cdiff += fn[i] - sn[i];
		ll trav = (fn.size() - i - 1) * 2;
		ans = min(ans, trav + cdiff + cans);
	}
	cout << ans << endl;
}
//DIFFERENCE IS ALL MESSED UP (STILL, BAH!)
Compilation message (stderr)
board.cpp: In function 'long long int getval(std::vector<int>&)':
board.cpp:58:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (int i = 0; i < cur.size(); i++) {
                  ~~^~~~~~~~~~~~
board.cpp: In function 'std::__cxx11::string printvect(std::vector<int>&)':
board.cpp:68:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (int i = 0; i < guy.size(); i++) {
                  ~~^~~~~~~~~~~~
board.cpp: In function 'int main()':
board.cpp:90:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (int i = 0; i < fguy.length(); ++i) {
                  ~~^~~~~~~~~~~~~~~
board.cpp:116:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (int i = 0; i < sguy.length(); ++i) {
                  ~~^~~~~~~~~~~~~~~
board.cpp:163:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (int i = 0; i < fn.size(); i++) {
                  ~~^~~~~~~~~~~
board.cpp:176:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (int i = 0; i < fn.size() && cdiff <= 300000; i++) {
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