Java | Counts
```\n public String greatestLetter(String s) {\n        int[] counts = new int[256];\n        for(char c : s.toCharArray()) {\n            counts[c]++;\n       
```\n public String greatestLetter(String s) {\n        int[] counts = new int[256];\n        for(char c : s.toCharArray()) {\n            counts[c]++;\n        }\n        \n        String resp = "";\n        for(int i=90;i>=65;i--) {\n            if(counts[i]>0 && counts[i+32]>0)\n                return (char)(i)+"";\n        }\n            \n            return "";\n            \n    }
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