#pragma GCC optimize("Ofast")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
#include <bits/stdc++.h>
using namespace std;

const int N = 10005;
const int INF = 0x3f3f3f3f;

int i, j, lv, ln, len, n, d[N], s[N], dp[2][N][2];

int main() {
  // FISIERE
  while(~scanf("%d", &n)) {
    for(i = 1; i <= n; ++i) scanf("%d %d", d + i, s + i);
    for(i = 1; i <= n; ++i) dp[0][i][0] = dp[0][i][1] = 0;
    for(lv = 0, ln = 1, len = 2; len <= n; ++len, swap(lv, ln))
      for(i = 1; i + len - 1 <= n; ++i) {
        j = i + len - 1;
        dp[ln][i][0] = min(dp[lv][i + 1][0] + d[i + 1] - d[i], dp[lv][i + 1][1] + d[j] - d[i]);
        if(dp[ln][i][0] > s[i]) dp[ln][i][0] = INF;

        dp[ln][i][1] = min(dp[lv][i][0] + d[j] - d[i], dp[lv][i][0] + d[j] - d[j - 1]);
        if(dp[ln][i][1] > s[j]) dp[ln][i][1] = INF;
      }
    if(min(dp[lv][1][0], dp[lv][1][1]) < INF) printf("%d\n", min(dp[lv][1][0], dp[lv][1][1]));
    else puts("No solution");
  }

  return 0;
}