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#include<stdio.h>
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int main()
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{
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int i,n,t,a[102];
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while(scanf("%d",&n),n)
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{
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for(i=0;i<n;i++)
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scanf("%d",&a[i]);
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t=a[0]+a[n-1];
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if(n%2!=0)
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printf("No\n");
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else
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{
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for(i=1;i<n/2;i++)
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if(a[i]+a[n-i-1]!=t)
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break;
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if(i==n/2)
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printf("Yes\n");
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else
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printf("No\n");
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}
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}
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return 0;
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}
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