#include <algorithm>

#include <cstdio>

#define maxn 30010

#define lc(rt) son[rt][0]

#define rc(rt) son[rt][1]

int son[maxn][2], fa[maxn], tg[maxn];

int w[maxn], S[maxn];

inline bool get(int rt, int tg = 1) { return son[fa[rt]][tg] == rt; }

inline bool is_root(int rt) { return !(get(rt, 0) || get(rt)); }

inline void update(int rt) {

	S[rt] = S[lc(rt)] + S[rc(rt)] + w[rt];

}

inline void pushdown(int rt) {

	if (tg[rt]) {

		tg[rt] ^= 1, tg[lc(rt)] ^= 1, tg[rc(rt)] ^= 1;

		std::swap(lc(rt), rc(rt));

	}

}

inline void rotate(int x) {

	int y = fa[x], z = fa[y], b = get(x);

	if (!is_root(y)) son[z][get(y)] = x;

	fa[son[y][b] = son[x][!b]] = y, son[x][!b] = y;

	fa[y] = x, fa[x] = z;

	update(y), update(x);

}

inline void splay(int x) {

	static int S[maxn], top;

	S[top = 1] = x;

	for (int y = x; !is_root(y); S[++top] = y = fa[y]) ;

	for (; top; top--) pushdown(S[top]);

	for (; !is_root(x); rotate(x)) if (!is_root(fa[x]))

		get(x) ^ get(fa[x]) ? rotate(x) : rotate(fa[x]);

	update(x);

}

inline void access(int x) { for (int t = 0; x; rc(x) = t, t = x, x = fa[x]) splay(x); }

inline void make_root(int rt) { access(rt), splay(rt), tg[rt] ^= 1; }

inline void link(int x, int y) { make_root(x), fa[x] = y; }

inline void split(int x, int y) { make_root(x), access(y), splay(y); }

inline void cut(int x, int y) { split(x, y), lc(y) = fa[x] = 0; }

inline int findroot(int x) {

	access(x), splay(x);

	while (lc(x)) x = lc(x), pushdown(x);

	splay(x);

	return x;

}

inline bool connected(int x, int y) {

	split(x, y);

	return x == findroot(y);

}

int n, m;

int main() {

	scanf("%d", &n);

	for (int i = 1; i <= n; ++i) {

		scanf("%d", w + i);

		S[i] = w[i];

	}

	scanf("%d", &m);

	while (m --> 0) {

		char op[15];

		int x, y;

		scanf("%s%d%d", op, &x, &y);

		switch (*op) {

			case 'b':

				if (connected(x, y)) puts("no");

				else {

					puts("yes");

					link(x, y);

				}

				break;

			case 'p':

				make_root(x);

				w[x] = y;

				update(x);

				break;

			case 'e':

				if (connected(x, y)) {

					split(x, y);

					printf("%d\n", S[y]);

				} else puts("impossible");

		}

	}

	return 0;

}