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#include <iostream>
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#include <string>
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#include <cstring>
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#include <vector>
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#include <cmath>
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#include <map>
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#include <algorithm>
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#include <climits>
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using namespace std;
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int S[1000005], cnt[1000005];
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int main() {
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  int n,A,B,lp = 0,targ,cur = 0,ans = INT_MAX;
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  scanf("%d%d%d",&n,&A,&B);
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  targ = B-A+1;
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  if(targ > n) {
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    printf("-1\n");
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    return 0;
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  }
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  for(int rp=0;rp<n;++rp) {
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    scanf("%d",&S[rp]);
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    if(S[rp] < A || S[rp] > B) {
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      while(lp < rp) {
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        --cnt[S[lp]-A];
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        ++lp;
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      }
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      ++lp;
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      cur = 0;
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      continue;
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    }
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    int& v = cnt[S[rp]-A];
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    ++v;
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    if(v == 1) ++cur;
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    while(cur == targ) {
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      ans = min(ans,rp-lp+1);
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      int& k = cnt[S[lp]-A];
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      --k;
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      if(!k) --cur;
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      ++lp;
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    }
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  }
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  if(ans == INT_MAX) printf("-1\n");
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  else printf("%d\n",ans);
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}