#include <bits/stdc++.h>
using namespace std;
const int N = 1e4 + 7;
const int inf = 0x3f3f3f3f;
const long long INF = 0x3f3f3f3f3f3f3f3f;
const int mod = 1e9 + 7;
const double eps = 1e-8;
const double PI = acos(-1);
char s[N];
int P, M, n, ans;
int mxdp[N][101], mndp[N][101], cnt[N];
int weight[N];
inline bool chkmax(int &a, int b) { return a < b ? a = b, true : false; }
inline bool chkmin(int &a, int b) { return a > b ? a = b, true : false; }
int getPos(int l, int r) {
  int w = 0, pos = -1;
  int digit = -1;
  for (int i = l; i <= r; i++) {
    if (s[i] == '(')
      w += 10000;
    else if (s[i] == ')')
      w -= 10000;
    else if (s[i] == '?')
      weight[i] = w;
    if (isdigit(s[i])) digit = i;
  }
  for (int i = l; i <= r; i++) {
    if (s[i] == '?') {
      if (pos == -1 || weight[pos] > weight[i]) pos = i;
    }
  }
  if (~pos) return pos;
  return digit;
}
void dfs(int l, int r, int rt) {
  if (s[rt] != '?') {
    mxdp[rt][0] = s[rt] - '0';
    mndp[rt][0] = s[rt] - '0';
    return;
  }
  int ls = getPos(l, rt - 1);
  int rs = getPos(rt + 1, r);
  dfs(l, rt - 1, ls);
  dfs(rt + 1, r, rs);
  cnt[rt] = cnt[ls] + cnt[rs] + 1;
  if (P < M) {
    for (int i = 0; i <= cnt[ls]; i++) {
      for (int j = 0; j <= cnt[rs]; j++) {
        if (i + j > P) continue;
        if (P - i - j > 0) {
          chkmax(mxdp[rt][i + j + 1], mxdp[ls][i] + mxdp[rs][j]);
          chkmin(mndp[rt][i + j + 1], mndp[ls][i] + mndp[rs][j]);
        }
        if (M - (cnt[ls] - i) - (cnt[rs] - j) > 0) {
          chkmax(mxdp[rt][i + j], mxdp[ls][i] - mndp[rs][j]);
          chkmin(mndp[rt][i + j], mndp[ls][i] - mxdp[rs][j]);
        }
      }
    }
  } else {
    for (int i = 0; i <= cnt[ls]; i++) {
      for (int j = 0; j <= cnt[rs]; j++) {
        if (i + j > M) continue;
        if (M - i - j > 0) {
          chkmax(mxdp[rt][i + j + 1], mxdp[ls][i] - mndp[rs][j]);
          chkmin(mndp[rt][i + j + 1], mndp[ls][i] - mxdp[rs][j]);
        }
        if (P - (cnt[ls] - i) - (cnt[rs] - j) > 0) {
          chkmax(mxdp[rt][i + j], mxdp[ls][i] + mxdp[rs][j]);
          chkmin(mndp[rt][i + j], mndp[ls][i] + mndp[rs][j]);
        }
      }
    }
  }
}
int main() {
  scanf("%s", s + 1);
  n = strlen(s + 1);
  scanf("%d%d", &P, &M);
  for (int i = 1; i <= n; i++)
    for (int j = 0; j <= min(P, M); j++) mxdp[i][j] = -inf, mndp[i][j] = inf;
  int root = getPos(1, n);
  dfs(1, n, root);
  printf("%d\n", mxdp[root][min(P, M)]);
  return 0;
}
