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$jscomp.initSymbolIterator=function(){$jscomp.initSymbol();var a=$jscomp.global.Symbol.iterator;a||(a=$jscomp.global.Symbol.iterator=$jscomp.global.Symbol("Symbol.iterator"));"function"!=typeof Array.prototype[a]&&$jscomp.defineProperty(Array.prototype,a,{configurable:!0,writable:!0,value:function(){return $jscomp.iteratorPrototype($jscomp.arrayIteratorImpl(this))}});$jscomp.initSymbolIterator=function(){}};
$jscomp.initSymbolAsyncIterator=function(){$jscomp.initSymbol();var a=$jscomp.global.Symbol.asyncIterator;a||(a=$jscomp.global.Symbol.asyncIterator=$jscomp.global.Symbol("Symbol.asyncIterator"));$jscomp.initSymbolAsyncIterator=function(){}};$jscomp.iteratorPrototype=function(a){$jscomp.initSymbolIterator();a={next:a};a[$jscomp.global.Symbol.iterator]=function(){return this};return a};$jscomp.underscoreProtoCanBeSet=function(){var a={a:!0},b={};try{return b.__proto__=a,b.a}catch(c){}return!1};
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$jscomp.generator.Context.prototype.jumpToErrorHandler_=function(){this.nextAddress=this.catchAddress_||this.finallyAddress_};$jscomp.generator.Context.prototype.next_=function(a){this.yieldResult=a};$jscomp.generator.Context.prototype.throw_=function(a){this.abruptCompletion_={exception:a,isException:!0};this.jumpToErrorHandler_()};$jscomp.generator.Context.prototype["return"]=function(a){this.abruptCompletion_={"return":a};this.nextAddress=this.finallyAddress_};
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$jscomp.generator.Context.prototype.jumpTo=function(a){this.nextAddress=a};$jscomp.generator.Context.prototype.jumpToEnd=function(){this.nextAddress=0};$jscomp.generator.Context.prototype.setCatchFinallyBlocks=function(a,b){this.catchAddress_=a;void 0!=b&&(this.finallyAddress_=b)};$jscomp.generator.Context.prototype.setFinallyBlock=function(a){this.catchAddress_=0;this.finallyAddress_=a||0};$jscomp.generator.Context.prototype.leaveTryBlock=function(a,b){this.nextAddress=a;this.catchAddress_=b||0};
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$jscomp.generator.Context.PropertyIterator=function(a){this.object_=a;this.properties_=[];for(var b in a)this.properties_.push(b);this.properties_.reverse()};$jscomp.generator.Context.PropertyIterator.prototype.getNext=function(){for(;0<this.properties_.length;){var a=this.properties_.pop();if(a in this.object_)return a}return null};$jscomp.generator.Engine_=function(a){this.context_=new $jscomp.generator.Context;this.program_=a};
$jscomp.generator.Engine_.prototype.next_=function(a){this.context_.start_();if(this.context_.yieldAllIterator_)return this.yieldAllStep_(this.context_.yieldAllIterator_.next,a,this.context_.next_);this.context_.next_(a);return this.nextStep_()};
$jscomp.generator.Engine_.prototype.return_=function(a){this.context_.start_();var b=this.context_.yieldAllIterator_;if(b)return this.yieldAllStep_("return"in b?b["return"]:function(a){return{value:a,done:!0}},a,this.context_["return"]);this.context_["return"](a);return this.nextStep_()};
$jscomp.generator.Engine_.prototype.throw_=function(a){this.context_.start_();if(this.context_.yieldAllIterator_)return this.yieldAllStep_(this.context_.yieldAllIterator_["throw"],a,this.context_.next_);this.context_.throw_(a);return this.nextStep_()};
$jscomp.generator.Engine_.prototype.yieldAllStep_=function(a,b,c){try{var d=a.call(this.context_.yieldAllIterator_,b);$jscomp.generator.ensureIteratorResultIsObject_(d);if(!d.done)return this.context_.stop_(),d;var e=d.value}catch(f){return this.context_.yieldAllIterator_=null,this.context_.throw_(f),this.nextStep_()}this.context_.yieldAllIterator_=null;c.call(this.context_,e);return this.nextStep_()};
$jscomp.generator.Engine_.prototype.nextStep_=function(){for(;this.context_.nextAddress;)try{var a=this.program_(this.context_);if(a)return this.context_.stop_(),{value:a.value,done:!1}}catch(b){this.context_.yieldResult=void 0,this.context_.throw_(b)}this.context_.stop_();if(this.context_.abruptCompletion_){a=this.context_.abruptCompletion_;this.context_.abruptCompletion_=null;if(a.isException)throw a.exception;return{value:a["return"],done:!0}}return{value:void 0,done:!0}};
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function main(a){return function(){a.split("\n");var b=null,c=null,d=null,e=null,f=0;c=$jscomp.makeIterator(a.split("\n"));b=c.next().value;c=c.next().value;d=parseInt(b);e=c.split(" ").map(function(a){return parseInt(a)});(function(){for(var a={},b=$jscomp.makeIterator(function g(a){var b,c;return $jscomp.generator.createGenerator(g,function(d){switch(d.nextAddress){case 1:if(0<=a){d.jumpTo(2);break}b=0;case 4:if(!(b>a)){d.jumpTo(0);break}return d.yield(b,5);case 5:b--;d.jumpTo(4);break;case 2:c=
0;case 8:if(!(c<a)){d.jumpTo(0);break}return d.yield(c,9);case 9:c++,d.jumpTo(8)}})}(d)),c=b.next();!c.done;a={$jscomp$loop$prop$i$3:a.$jscomp$loop$prop$i$3},c=b.next())a.$jscomp$loop$prop$i$3=c.value,function(a){return function(){return e[a.$jscomp$loop$prop$i$3]!=a.$jscomp$loop$prop$i$3+1?f+=1:null}}(a)()})();return console.log(2>=f?"YES":"NO")}()}main(require("fs").readFileSync("/dev/stdin","utf8"));


Measured memory_bytes: 7372